Which of the following statements is correct statements?
a) Moderate decrease or increase of micronutrients causes deficiency and toxicity symptoms respectively.
(b) Excess of manganese causes toxicity of iron, calcium and molybdenum.
(c) A macronutrient is said to be toxic when present below a critical concentration.

The correct option is B Only (a) is correct
The correct answer is "option A"

• Moderate decrease of micronutrients causes deficiency in plants and excessive intake of minerals or micronutrient is called toxicity. Both conditions are adverse for plants.

• Excess of manganese causes deficiencies of iron, calcium and molybdenum.

• A macronutrient is said to be toxic when present above a critical concentration.